Packet communication has proven to be an economically practical system for the transmission of information which occurs in short, high-rate bursts with long pauses in between bursts. The use of packet communication allows efficient utilization of the switching and transmission facilities, since the facilities are only utilized during the actual transmission of information.
The transmission of voice information in the form of packets is a desirable communication technique; however, it is not as yet in widespread commercial use. Packetization of voice would not only result in a more economic and effective communication system, but it would also facilitate the introduction of totally integrated voice and data service on a nationwide basis.
An important constraint on an integrated packet communication system has been that packets of encoded voice must be received at their destination within a maximum amount of time after transmission from their source. If this constraint is not met, then the packets cannot be used for voice conversation because the fidelity of the voice reproduction would deteriorate.
Prior art systems for switching packets have been rather small systems consisting of only a few hundred nodes with limited packet handling capability--that is, being capable of only handling a few thousand packets per second. A disadvantage of such systems is their need to equip each switching node with complex computers and sophisticated software packages to perform the packet switching function. The systems customarily have used complex control protocols to handle error recovery and flow control and, as a result, have had the limited packet handling capability.
A problem in the prior art which contributed to packet switching delays is the requirement for a central computer translation of address information in each packet as it progresses through the packet switching system. Such translations are time consuming operations for the computer and contribute to packet delays and traffic congestion in the networks and at the computer, particularly during heavy traffic periods. Illustratively, as each packet is received by a packet switching network, the prior art required a central computer to translate logical address information in the received packet into physical address information needed to switch that packet through the network to its intended destination.
In view of the foregoing, a need exists for facilities which reduce the burdens on central computers in performing translations for each received packet and particularly for improved facilities for performing the logical to physical address translations for packet switching functions with minimal delays. A specific need exists for packet switching control arrangements which facilitate the communication of voice signals with fidelity unimpaired by objectionable delays.